Living side-by-side are two Zubkis families. Only males are enumerated here, and the ages are those that they were in 1859.

Household #71

(Zubkis) Baranovski Shmuel son of Srul (born ~1851)

Moved to M. Mikhailovka, Litin Uezd (note that this is where Avrum Zubkis moved to as well)

Household #72

Zubkis Mortko, son of Yosef (born ~1822)

his son Srul (born ~1855)

his son Nus (born ~1856)

Moved to Skarbka, Litin uezd

There is also a death record for a Kuna-registered Zubkis who died in the nearby (slightly-larger) town of Gaisin:

Gaisyn book of registration of deaths of Jews for 1899, #18, Mordechai Zubkis - Hebrew

Gaisyn book of registration of deaths of Jews for 1899, #18, Mordechai Zubkis -Russian

Mordechai Zubkis, son of Nus/Nossin Zubkis, died on May 10 (13 Sivan), 1899. He was registered in Kuna, was 88 years old (implying a birth year around 1811), and he died of old age.

With the multiple given names in common with the Mordechai Zubkis and family from the 1875 Kuna revision list, it's obvious that there are common ancestors. Hopefully the puzzle pieces will come together soon.